The US branches of TD Bank used to have coin counting machines in them. Customers would lug bags of change they found to the bank to have them automatically counted and they could be redeemed for a deposit credit or cash on the spot. It turned out, they had been skimming them for years and undercounting the coins. They had to pay out $10 million in a class action settlement. They were literally nickel-and-diming people and thought nobody would notice!